Bitumen compositions are widely used in the construction industry as adhesives, waterproofing agents, and preservatives. Bitumen compositions modified by certain thermoplastics and elastomers are known. For example, U.S. Pat. No. 4,818,367 to Winkler describes an asphalt composition containing an asphalt, a copolymer of an olefin with an anhydride or a nitrile, and an unsaturated elastomer having at least two terminal groups each with an active hydrogen, a halogen, an epoxy oxygen or a cyanocarbon. U.S. Pat. No. 5,280,064 to Hesp et al. describes compositions prepared by vulcanization of a bitumen and an amine-terminated poly(butadiene-co-acrylonitrile), followed by coupling of this vulcanization product with carboxylated polyethylene. U.S. Pat. No. 5,719,215 to Liang et al. and U.S. Pat. No. 5,959,007 to Liang describe compositions comprising bitumen and treated rubbers derived from automobile tires. U.S. Pat. No. 6,100,317 to Liang et al. describes compositions comprising bitumen, a sterically stabilized polyolefin, and another polymer, such as a styrene-butadiene-styrene copolymer, an ethylene-vinyl acetate copolymer, or an EPDM copolymer. U.S. Pat. No. 6,174,939 to Liang describes compositions comprising bitumen, a styrenic polymer, and a triblock copolymer as a compatibilizing agent.
One embodiment of the invention is a composition comprising: a poly(arylene ether) having an intrinsic viscosity less than 0.4 deciliters/gram at 25xc2x0 C. in chloroform; and a bitumen.
Another embodiment of the invention is a composition comprising the reaction product of: a poly(arylene ether) having an intrinsic viscosity less than 0.4 deciliters/gram at 25xc2x0 C. in chloroform; and a bitumen.
Another embodiment of the invention is an article comprising either of the above compositions.
Another embodiment of the invention is a method of preparing a composition, comprising: blending a poly(arylene ether) and a bitumen; wherein the poly(arylene ether) has an intrinsic viscosity less than 0.4 deciliters/gram at 25xc2x0 C. in chloroform.
One embodiment of the invention is a composition comprising: a poly(arylene ether) having an intrinsic viscosity less than 0.4 deciliters/gram at 25xc2x0 C. in chloroform; and a bitumen.
The composition may comprise any conventional poly(arylene ether). The term poly(arylene ether) includes polyphenylene ether (PPE) and poly(arylene ether) copolymers; graft copolymers; poly(arylene ether) ether ionomers; and block copolymers of alkenyl aromatic compounds, vinyl aromatic compounds, and poly(arylene ether), and the like; and combinations comprising at least one of the foregoing; and the like. Poly(arylene ether)s are known polymers comprising a plurality of structural units of the formula: 
wherein for each structural unit, each Q1 is independently halogen, primary or secondary C1-C12 alkyl, phenyl, C1-C12 haloalkyl, C1-C12 aminoalkyl, C1-C12 hydrocarbonoxy, or C1-C12 halohydrocarbonoxy wherein at least two carbon atoms separate the halogen and oxygen atoms; and each Q2 is independently hydrogen, halogen, primary or secondary C1-C12 alkyl, phenyl, C1-C12 haloalkyl, C1-C12 aminoalkyl, C1-C12 hydrocarbonoxy, or C1-C12 halohydrocarbonoxy wherein at least two carbon atoms separate the halogen and oxygen atoms. Preferably, each Q1 is independently C1-C12 alkyl or phenyl, especially C1-4 alkyl, and each Q2 is independently hydrogen or methyl.
Both homopolymer and copolymer poly(arylene ether)s are included. The preferred homopolymers are those comprising 2,6-dimethyl-1,4-phenylene ether units. Suitable copolymers include random copolymers comprising, for example, such units in combination with 2,3,6-trimethyl-1,4-phenylene ether units or copolymers derived from copolymerization of 2,6-dimethylphenol with 2,3,6-trimethylphenol. Also included are poly(arylene ether)s containing moieties prepared by grafting vinyl monomers or polymers such as polystyrenes, as well as coupled poly(arylene ether) in which coupling agents such as low molecular weight polycarbonates, quinones, heterocycles and formals undergo reaction in known manner with the hydroxy groups of two poly(arylene ether) chains to produce a higher molecular weight polymer. Poly(arylene ether)s may further include combinations of any of the above.
The poly(arylene ether) may have a number average molecular weight of about 500 to less than 20,000 atomic mass units (amu), preferably about 1,000 to about 10,000 amu, more preferably about 1,250 to about 9,000 amu. The poly(arylene ether) may have a weight average molecular weight of about 1,000 to less than 40,000 amu, preferably about 2,000 to about 30,000 amu, more preferably about 2,500 to about 20,000 amu. Both number and weight average molecular weights may be determined by gel permeation chromatography using polystyrene standards. The poly(arylene ether) may have an intrinsic viscosity less than 0.4 deciliters per gram (dl/g), preferably less than about 0.35 dl/g, more preferably less than about 0.30 dl/g, yet more preferably less than about 0.20 dl/g, as measured in chloroform at 25xc2x0 C. The poly(arylene ether) may have an intrinsic viscosity greater than about 0.05 dl/g, preferably greater than about 0.08 dl/g, as measured in chloroform at 25xc2x0 C.
The poly(arylene ether)s are typically prepared by the oxidative coupling of at least one monohydroxyaromatic compound such as 2,6-xylenol or 2,3,6-trimethylphenol. Catalyst systems are generally employed for such coupling; they typically contain at least one heavy metal compound such as a copper, manganese, or cobalt compound, usually in combination with various other materials. Suitable methods for the preparation and isolation of poly(arylene ether)s are disclosed in, for example, U.S. Pat. No. 3,219,625 to Blanchard et al., U.S. Pat. No. 3,306,875 to Hay, U.S. Pat. No. 4,028,341 to Hay, U.S. Pat. No. 4,092,294 to Bennett, Jr. et al., U.S. Pat. No. 4,440,923 to Bartmann et al., and U.S. Pat. No. 5,922,815 to Aycock et al.
Preferred poly(arylene ether)s may have a low level of amine incorporation. Poly(arylene ether)s are often synthesized under conditions that result in incorporation of amine catalysts, such as dibutylamine, into the polymer. For example, when using dibutylarnine (DBA) in the polymerization process, the amount of DBA incorporated into a high-intrinsic viscosity (e.g., 0.48 dL/g) poly(arylene ether) may be about 0.9-1.0 weight percent, calculated as 100 times the weight of incorporated dibutylamine divided by the total weight of the poly(arylene ether). In comparison, methods for synthesis of low-intrinsic viscosity poly(arylene ether) may result in lower incorporation of amine. For example, the level of dibutylamine incorporated into low molecular weight (e.g., 0.11 dL/g) poly(arylene ether) may be about 0.15 to about 0.28 weight percent. It is desirable to use poly(arylene ether) with low incorporated amine content to minimize the amount of amine that may become thermally liberated during subsequent processing and may adversely affect properties of the composition. For this reason, it is generally preferred that the poly(arylene ether) comprise less than about 0.5 weight percent of amine, preferably less than about 0.3 weight percent of amine, calculated as 100 times the weight of incorporated dibutylamine divided by the total weight of the poly(arylene ether). Method for determining the amine content of poly(arylene ether)s are known in the art and include, for example, titration of the poly(arylene ether) with perchloric acid in the presence of an indicator system comprising 1-naphthol and mercuric acetate.
The amount of poly(arylene ether) in the composition may vary widely and will depend on the ultimate use of the composition and the presence of other components. In general, the composition may comprise at least about 0.1 weight percent, preferably at least about 0.5 weight percent, more preferably at least about 1 weight percent, based on the total weight of the composition. The composition may comprise up to about 99 weight percent, preferably up to about 20 weight percent, more preferably up to about 10 weight percent, of the poly(arylene ether) based on the total weight of the composition.
Bitumen, as employed in the composition, refers to a class of black or dark-colored solid, semi-solid, or viscous cementitious substances, natural or manufactured, composed principally of high molecular weight hydrocarbons. A common source of bitumen is as a bi-product of petroleum refining. Materials comprising bitumen may include straight asphalt, semi-blown asphalt, blown asphalt, tar, pitch, cutback asphalt, asphalt emulsion, and the like.
Bitumen may be characterized by its penetration grade. Penetration grade is determined by a needle penetration test and expressed as the extent to which a needle penetrates a prepared sample. Penetration may be measured according to ASTM D5-97 (Standard Test Method for Penetration of Bituminous Materials). The results are reported in units of 0.1 millimeter (sometimes expressed without the millimeter dimension), with 0 being very hard and 300 being very soft. While selection of a particular penetration grade will depend on the ultimate use for the composition, penetration grades of about 150 to about 220 may be preferred. Bitumens may also be characterized by their level of asphaltenes. To improve the compatibility of the bitumen with the poly(arylene ether), it is preferred that the asphaltene content should be as low as possible, preferably less than 12 weight percent of the total bitumen. The asphaltene content of bitumen may be determined according to ASTM D6560 (Standard Test Method for Determination of Asphaltenes (Heptane Insolubles) in Crude Petroleum and Petroleum Products).
The composition may comprise at least about 1 weight percent, preferably at least about 50 weight percent, more preferably at least about 80 weight percent bitumen, based on the total weight of the composition. The composition may comprise up to about 99.9 weight percent, preferably up to about 99 weight percent, more preferably up to about 95 weight percent of the bitumen, based on the total weight of the composition.
The composition may, optionally, comprise a block copolymer of an alkenyl aromatic compound and a conjugated diene (hereinafter a xe2x80x9cblock copolymerxe2x80x9d). The block copolymer is a copolymer comprising (A) at least one block derived from an alkenyl aromatic compound and (B) at least one block derived from a conjugated diene. The arrangement of blocks (A) and (B) includes a linear structure, a grafted structure, and a radial teleblock structure having a branched chain. The block copolymer includes materials in which the aliphatic unsaturated group content in the block (B) is reduced by hydrogenation.
Preferred of these structures are linear structures embracing diblock (A-B block), triblock (A-B-A block and B-A-B block), tetrablock (A-B-A-B block), and pentablock (A-B-A-B-A block and B-A-B-A-B block) structures as well as linear structures containing 6 or more blocks in total of A and B. More preferred are diblock, triblock, and tetrablock structures, with the A-B-A triblock structure being particularly preferred.
The alkenyl aromatic compound providing the block (A) is represented by formula: 
wherein R1 and R2 each independently represent a hydrogen atom, or a C1-C8 alkyl group; R3 and R7 each independently represent a hydrogen atom, a C1-C8 alkyl group, a chlorine atom, or a bromine atom; and R4, R5, and R6 each independently represent a hydrogen atom, a C1-C8 alkyl group, or a C2-C8 alkenyl group, or R6 and R7 are taken together to form a naphthyl group, or R5 and R6 are taken together to form a naphthyl group.
Specific examples of the alkenyl aromatic compounds include styrene, p-methylstyrene, alpha-methylstyrene, vinylxylene, vinyltoluene, vinylnaphthalene, divinylbenzene, bromostyrene, and chlorostyrene, and combinations comprising at least one of the foregoing alkenyl aromatic compounds. Of these, styrene, alpha-methylstyrene, p-methylstyrene, vinyltoluene, and vinylxylene are preferred, with styrene being more preferred.
Specific examples of the conjugated diene include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and the like. Preferred conjugated dienes include 1,3-butadiene and 2-methyl-1,3-butadiene, with 1,3-butadiene being more preferred.
In addition to the conjugated diene, the block copolymer may contain a small proportion of a lower olefinic hydrocarbon, including, for example, ethylene, propylene, 1-butene, dicyclopentadiene, non-conjugated dienes, and the like.
In one embodiment, the block copolymer comprises alkenyl aromatic blocks having a total number average molecular weight of at least about 5,000 atomic mass units (amu), preferably at least about 10,000 amu, more preferably at least about 12,000 amu.
There is no particular limitation on the mode of incorporation of the conjugated diene in the hydrogenated block copolymer backbone. For example, when the conjugated diene is 1,3-butadiene, it may be incorporated with about 1% to about 99% 1,2-incorporation with the remainder being 1,4-incorporation.
When the block copolymer is hydrogenated, it may be hydrogenated to such a degree that fewer than 50%, more preferably fewer than 20%, yet more preferably fewer than 10%, of the unsaturated bonds in the aliphatic chain moiety derived from the conjugated diene remain unreduced. The aromatic unsaturated bonds derived from the alkenyl aromatic compound may be hydrogenated to a degree of up to about 25%.
The block copolymer preferably has a number average molecular weight of about 5,000 to about 500,000 amu, more preferably about 10,000 to about 300,000 amu, yet more preferably about 30,000 to about 200,000 amu, and even more preferably about 45,000 to about 180,000 amu, as determined by gel permeation chromatography (GPC) using polystyrene standards.
The block copolymer may be prepared by known methods or obtained commercially. Suitable commercially available block copolymers include, for example, those materials available from Kraton Polymers under the trade name KRATON(copyright). These materials include the unhydrogenated block copolymers in the KRATON(copyright) D series, such as, for example, the block poly(styrene-butadiene-styrene) materials KRATON(copyright) D1101, D1144X, D1184, and D1188; and the hydrogenated block copolymers in the KRATON(copyright) G series, such as, for example, the block poly(styrene-(ethylene-butylene)-styrene) materials KRATON(copyright) G1650 and G1652.
When present in the composition, the block copolymer may be used at greater than about 1 weight percent, preferably greater than about 2 weight percent, more preferably greater than about 5 weight percent, based on the total weight of the composition. The block copolymer may be used at less than about 30 weight percent, preferably less than about 20 weight percent, more preferably less than about 15 weight percent.
When the composition comprises a block copolymer of an alkenyl aromatic compound and a conjugated diene, the weight ratio of the block copolymer to the poly(arylene ether) may preferably be at least about 3:1, more preferably at least about 4:1.
The composition may, optionally, comprise one or more additives known in the art, including, for example, curing aids, activators, retarders, accelerators, processing aids, plasticizers, fillers, reinforcing agents, antioxidants, antiozonants, flame retardants, peptizing agents, coupling agents, gelling agents, and the like, and mixtures comprising at least one of the foregoing additives. Fillers that may be used in the composition include, for example, limestone, slate dust, talc, fly ash, carbon black, and the like, and mixtures comprising at least one of the foregoing fillers.
In one embodiment, the composition may comprise about 1 to about 3 weight percent of a poly(arylene ether) having an intrinsic viscosity less than 0.4 deciliters/gram at 25xc2x0 C. in chloroform; about 5 to about 15 weight percent of a block copolymer of an alkenyl aromatic compound and a conjugated diene; and about 50 to about 94 weight percent bitumen; wherein all weight percents are based on the total weight of the composition.
In another embodiment, the composition may comprise about 1 to about 3 weight percent of a poly(arylene ether) comprising poly(2,6-dimethyl-1,4-phenylene ether) having an intrinsic viscosity less than 0.2 deciliters/gram at 25xc2x0 C. in chloroform; about 5 to about 15 weight percent of block-poly(styrene-butadiene-styrene), block-poly(styrene-(ethylene-butylene)-styrene), or a mixture comprising at least one of the foregoing; and about 50 to about 94 weight percent bitumen; wherein all weight percents are based on the total weight of the composition.
In one embodiment, the composition may preferably exhibit a ring and ball softening point according to NEN-EN 1427 of at least about 85xc2x0 C., more preferably at least about 90xc2x0 C.
In one embodiment, the composition may preferably exhibit a penetration point according to NEN-EN 1426 less than about 0.55 mm, more preferably less than about 0.50 mm.
In one embodiment, the composition may preferably exhibit a flow temperature according to PrEN 1110 of at least about 70xc2x0 C., preferably at least about 75xc2x0 C.
The composition may be prepared by blending the poly(arylene ether) and the bitumen to form an intimate mixture. Blending is generally conducted at a temperature of at least about 180xc2x0 C. Blending may also be conducted at a temperature of at least about 210xc2x0 C. Blending may be facilitated by using a powdered form of the poly(arylene ether). Specifically, in one embodiment it is preferred to use a milled poly(arylene ether)s having an average particle size not greater than about 200 micrometers, more preferably not greater than about 100 micrometers, yet more preferably not greater than about 75 micrometers, even more preferably not greater than about 50 micrometers. In another embodiment, it may be preferably to use a powdered poly(arylene ether) having an average particle size of about 20 to about 200 micrometers. Powdered poly(arylene ether) materials may be prepared by grinding commercially available pellets using grinding techniques known in the art.
When the composition comprises a block copolymer of an alkenyl aromatic compound and a conjugated diene, it may be prepared by blending the poly(arylene ether) and the block copolymer to form a first intimate mixture; and blending the first intimate mixture and bitumen to form a second intimate mixture.
The composition is, for example, useful as a preservative, as a waterproofing agent, and as an adhesive agent in building and construction. The composition""s high heat resistance is particularly useful in high-temperature applications, such as those in which the composition is applied by mopping or torching. The composition is also particularly useful in warmer climates. Articles comprising the composition may include, for example, roofing materials, such as bitumen membranes.